Some optical switches permit any-to-any connections. In this case, the optical switch connects one of several male fiber connectors to one of several female fiber connectors. Proper cleaning of the optical switch continues to be an issue faced by optical switch manufacturers and users.
Any contamination in the fiber connection can greatly degrade performance or cause the optical switch to fail. Mechanical dust can occur due to the rubbing and/or touching that often occurs when mating two fiber connectors together. Even microscopic dust particles can cause a variety of problems for optical connections. A particle that partially or completely blocks a fiber core can generate strong back reflections that can cause instability in the optical switch. Dust particles trapped between two fiber faces can scratch the glass surfaces, which can lead to high decibel (dB) loss. Even if a particle is only situated on a cladding or an edge of the fiber face, it can cause an air gap or a misalignment between the fiber cores, which can significantly degrade the optical signal.
In addition to dust, other types of contamination can also accumulate on fiber connectors. Examples of these types of contamination include oils (e.g., frequently from human hands), residues (e.g., condensed air vapors), and powdery coatings (e.g. left after water or other solvents evaporate). These contaminants can be more difficult to remove than dust particles and can also cause damage to the optical switch if not removed.
Manual techniques exist for fully cleaning male fiber connectors, but such techniques often are insufficient for properly cleaning female fiber connectors. Blowing or sucking tools have been used to clean dust particles from within a female fiber connector, but these tools may have insufficient strength to overcome the high static forces that can occur within the female connector. A swab can be used to clean other types of contaminants from within a female connector, but the swab typically cannot fully eliminate the contaminants.